Wireless-telegraph receiver



E. W. B. GIEL. WIRELESS TELEGRAPH RECEIVER. APPLICATION FILED 00T. 7, 1920.

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WIRELESS-mantenerla RECEIVER- Specification of Lettersrlatent. Patented Maru 159 192ML Application medoc/wher 7, i920. serial No. laica To all whom t may concern.' l

Be it known that I, ERNEST WALTER BRU- DENELL GILL, a subject of the King of Great Britain, residing at Merton College, Ox-

ford,-England, have invented certain new and useful Improvements in Wireless-Telegraph Receivers, of which the following is a speciication.

This.- invention relates to wireless telegraph receivers of the type in which the signals to be received act upon the grid of a valve, the anode of which is connected di- `rectly to the grid of a second valve, while the variations in the current in the anode circuit of this second valve act upon a current indicator such as a telephone receiver.'

According to .this invention I provide means for adjusting the voltageof the first lgrid so thatv the current in the anode circuit of the second valve may decrease 'as Ithe voltage of the first grid increases, and.

increases as the voltage of the first grid decreases, or in other words the anode current;

,of the second valve is varied inversely with 'the potential of the grid of the irst valve through a portion of a cycle.

In accordance with this invention the voltage of the lirst grid may also be ad'usted with respect to the' signal strengt lso thatthie variations of the current,v of ,the anode of the second valve occur'between the same limiting values of maxima and minima for all signals above apredetermined signal strength.

Preferably also the` negative side of a small battery is connected to the'irst grid.

My invention is illustrated by the accompanying drawing, 1

@Figure l is a diagrammatic view of a receiving system. in accordance with the invention. y

Fig. 2 is a curve showing the relation of the anode current in the second valve to the grid voltage of the rst valve.

Fig. 3 shows a number of anode currentrid voltage curves with diierent values or" lament current.

Fig. 4 shows a number of anode currentgrid voltage curves with diHerent values of anode voltage.

In Fig. l Fv f are the laments, Gr g the .Grids and A a the anodes of two valves, the :filaments being connected iii parallel to a battery B through a resistance R. The

anode A and the grid g are connected-together, but otherwise they are insulated. VThe voltage of the grid G can be adjusted by means of a potentiometer P, a small battery C being inserted 'between' the potentiome'ter and t'he grid and having its negative side connected to the latter. D is a tuned oscillatory circuit loosely coupled to an aerial E. The anode a is connected through Such an arrangement gives a charactera telephone T and a battery fV to the lila- 'I istie of theforni shown in Fig. 2, the 'alnscissae' bein and grid and the ordinates being the values of the current in the circuit of the anode (1 'It will bese/erithat as the grid G has its potential' increased (positively) with regard to the filament F, the anode current of the second valve is approximately constant from K to L; from L to M it decreases, and then becomes` approximately constant again from M onward. From Ll to M the combination has a negative resistance, z. e. increase of applied volts results in a diminution ofthe current; and the arrangement has two rectifying, points L Yaudit/fl. l u

y The curves in Fig. 3 show the eiiect of varying the filament currents, keeping the' -plate voltage fixed, while those in Fig. 4 give `the result of keeping the filament current constant and varying the plate voltage. In both thesefigures the abscissae are grid volts and the ordinates anodevcurrents in microampere's. In Fig. 3 thev dierence in volts betweenthe filament 'potential between the anode a and the la- 'ment f is constant and equal to 40 volts, while the ilament current in amperes is l shown by the gures tothe right yoi? each `curve, the -filament currents fin t e two vvalves being approximately equal. Similar results can be obtained by varying the fila` ment current of the irst valve only, keeping the second constant, the filament cui'- rent of the first valve bein the determining factor. in Fig. 4 the eating current is .53 amperes for all three curves, while'the anode volts are shown by the figures to the rivht of each curve.

#Fig l shows that there is only one result from in creasin the plate voltage |of the sec'- ond valve, an that is to increase the' current drop; the place on the'potentiometer where the drop begins and ends being about the same for all plate volts; increase 1n plate volts therefore increases the steepness of the curve. I

Fig. 3 on the other'hand shows that varia tion of the filament current has no appreciable effect on the steepness but determines the extent of the drop. lHence by suitably adjusting the plate volts and the filament current an desired curve in reason can be 'l obtained, for instance, .a small steep drop 'can be'obtained--by using a large plate volt- (2) Discrimination between different types ofi si als. 4

'l/Vith regard to (l), the maximum rectification depends on the drop from L to M, if therefore this drop is iiiade small, which can lv done as explained above, all signals i over a'certain strength will give sounds of equal strength in the telephone. i lVith regard tol (Qbetween the two rectifying points L and mum, and it has been found experimentally that the positions of these minima differ for different types of sending gear. Thus the minimum for a Telefunken is not the same as for a British navy spark, and it is pos; sible if their strengths are about the same to hear the Telefunken only on one adjustment, and the navy only on another adjustment. Disturbances due to certain types of' atmospherics can also be reduced relatively to the signals it is required to receive.

` Having now particularly described and ascertained the nature of my said invention `and in what manner the same is to be performed, I declare that what I claim is l. In a wireless telegraph receiver the combination of two valves each having a grid, an anode and a cathode, thecathodes being at substantially the same potential, means for 'causin incoming signals to aect the grid ofthe figrst valve, a low resistance connection between;4 the anode of the'iffirst valve and the grid of lthe second valve whereby these are at the same potential and an indicator actuated lby variationsin the anode current of the second valve.

2. ln a wireless telegraph receiver a combination of two valves each havinga grid, an anode and a cathode, the'cathodes being at substantially the sainepotentiaha battery having the negative side connected to)vf signals go to a mini- I the grid of the first valve, means for causing incoming signals to affect said grid, a low resistance connection between the anode of the first valve and the grid of the .second valve whereby these are at the same potential and a detector actuated by variations in the anode current of the second valve.

, 3. ln -a wireless telegraph receiver, the

combination of two valves, each having a grid, an anode and a cathode, the cathodes being at substantially the same potential, a battery having the negative side connected to the grid of the first valve, means for causing current of the second valve.

l. In awireless telegraph receiver the combination of two valves each having a grid, ananode and a cathode, the cathodes being at substantially the saine potential, the anode of the first valve being 'disposed to accumulate a charge from its cathode, means for causing incoming signals to affect thel grid of the first valve whereby the charge on the anode is varied, a low resist-` ance connection between the anode of' the first valve and the grid of bthe second valve whereby these are at the saine potential and an indicator actuated by variations in the anode current of the second valve.

5. In a wireless telegraph receiver the combinationof two valves each having a' 'incoming signals to affect said grid, a low grid, an anode and a cathode, the cathodes being at substantiallyl the same potential,

'the anode of the first valve being disposed to accumulate a charge from its cathode, a battery having the negative side connected to the grid of the first valve, means for'caus'* ingI incoming signals to affect said grid whereby the charge on the anode is varied,- a low, resistance connection between the 'anode of the first valve and the grid of the second valve whereby these are at the same potential and a detector actuated bythe variations in the anode current of the second valve.

6. In a wireless telegraph receiver theycombination of two valves each having a grid. an anode and a cathode, the cathodesbeing at substantially the same potential, the anode of the first valve being disposed to accumulate acharge from its cathode, la battery having the negative side connected to the grid of the first valve, means for causin incoming signals toafect said grid whereby the charge on the anode ,is varied, a lowr `sistance connection between the anode 0f the first valve and the grid of the second valve whereby these are at thesarne potential, a battery connected between the anode v heviger and thc cathode of the second valve and an iui'licator actuated by variations in the anode current of' the second val-ve.

T. ln wireless telegraph receivers the conibination of two valves each having a grid, au anode and a cathode t-he anode of the first valve being disposed to accumulate the charge from its cathode, a battery connected to the grid of the first'valve, means for causing incoming signals to affect said grid whereby the charge on the anode is varied, a connection between the anode of the first valve and the grid of the second valve, and an indicator actuated by variations in the anodecurrent of the second valve.

S. In a wireless telegraph receiver the combination of two valves each having acathode. ananode and a grid, the anode of' the first valve being disposed to accumulate a charge from its cathode, a battery having the nega-tive side connected to the grid of the first valve, means for causing incoming signals to affect said grid whereby the charge on the anode is varied, a connection between the anode of the first va-lve and the grid of the second valve, a battery connected between the anode and cathode ofthe second valve and an indicator actuated by variations in the anode current of the second valve'. i

9. In a wireless telegraph receiver .the

combination of two valves each having al cathode, an anode and a grid, the anode of the first valve being disposed to accumulate a charge from its cathode, a battery having the negative side connected to the grid of the first valve. means for causing incoming signals to affect said grid whereby the charge on the anode is varied, a connection between the anode of the first valve and the grid of the second valve, means for varying the electron emission of the cathodes and an indicator actuated by variations in the anode current of the second valve, the voltage applied to the grid being adjusted so that the anode current of the second valve vvaries inv versely with the potential of the grid of the first valve and the electron emission of the valves being adjusted so that said anode current varies between the same limiting values for all efiects above a pre-determined signal strength.

l0. In wireless telegraph receivers the combination of two valves each having'a grid` an anode and a cathode, the anode of the first valve being disposed to receive a charge from its cathode, a battery connected to the grid of the first valve, means for causing incomingv signals to affect said grid whereby the charge of the anode is varied, a connection between the anode of the first valve and the grid of the second valve, an indicator actuated by variations in the anode current of the second valve, the voltage aps` plied to the grid of the first valve being adjusted so that the anode current of the second valve varies inversely with the potential of the grid of the first valve when said grid is subjected to incoming signals.l

l1. In a wireless telegraph receiver the combination of two valves each having a cathode, an anode and a grid, the anode 'of disposed to receive a e the first valve being charge from its cathode, a battery having the negative side connected to the grid of the first valve, means for causing incoming signals to affect said grid whereby the' charge on the anode is varied, a connection c between the anode of the first valve and the grid of the second valve, a battery connected between the anode and cathode of the second valve and an indicator actuated by variations in the anode current ofthe second valve, the voltage applied to said grid being adjusted so that the anode current of the second valve varies inversely with the potential of the grid of the first valve when the grid is subjected to signals and the voltage applied to the anode of the second valve being adjusted so that said anode current varies between the same limiting values for all the effects above a predetermined signal strength.

In testimony whereof I have hereunto afiixed my signature this twenty first day of September 1920.

ERNEST WALTER BRUDENLL GlLL. 

